Temperature and Strain Rate Dependent Tension Properties of Stainless Steel-Aluminum-Magnesium Multilayered Sheet Fabricated by Roll Bonding

DOI : 10.5228/KSTP.2011.20.3.257͑

͑

穢剳暒昷儆击穟箒滆V洢YW劒G 洢Z笾SGYWXX噊VY\^G

G

嵪 橛櫶夢 STS-Al-Mg 決涋匎暓砖沲汞 欮壊歆 懆笛氮暓壊櫖 娶幾 1犛汾沫 懆笛瞿昷

G

筯憚勢¹· 決列昣¹· 筓朢汻²· 決欇昦^# G

Temperature and Strain Rate Dependent Tension Properties of Stainless Steel-Aluminum-Magnesium Multilayered Sheet

Fabricated by Roll Bonding

G

B. K. Hwang, K. S. Lee, S. E. Hong, Y. S. Lee

(Received April 22, 2011 / Revised May 18, 2011 / Accepted May 23, 2011) G

Abstract

Multilayer(clad) sheets, composed of two or more materials with different properties, are fabricated using the roll-bonding process. A good formability is an essential property for a multilayered sheet in order to manufacture parts by plastic deformation. In this study, the influences of temperature and strain rate on the plastic properties of stainless steel-aluminum- magnesium multilayered(STS-Al-Mg) sheets were investigated. Tensile tests were performed at various temperatures and strain rates on the multilayered sheet and on each separate layer. Fracture of the multilayered sheet was observed to be temperature-dependent. At the base temperature of 200°C, all materials fractured simultaneously. At lower temperatures, the Mg alloy sheet fractured earlier than the other materials. Conversely, the other materials fractured earlier than the Mg alloy sheet at higher temperatures. The uniform and total elongations of the multilayered sheet were observed to be higher than that of each material at a temperature of 250°C. Larger uniform elongations were obtained for higher strain rates at constant temperature. The same trend was observed for the Mg alloy sheet, which exhibited the lowest elongation among the three materials. The tensile strengths and elongations of the single layer sheets were compared to those of the multilayer material. The strength of the multilayered sheet was successfully calculated by the rule of mixture from the values of each single layer. However, no simple correlation between the elongation of each layer and that of the multilayer was obtained.

G G

Key Words : Multilayered Sheet, Tensile Test, Strain Rate, Plastic Deformation

41# ⇆# ᤊG G

㧊㫛⁞㏣ 䕦㨂(multilayered sheet; ┺䂋䕦㨂, 䋊⧮

✲ 䕦㨂⧒ἶ☚ 䞾.)⓪ ⽋䞿㨂⬢㦮 㧒㫛㦒⪲ ㍲⪲

㎇㰞㧊 ┺⯎ ⚮ ⡦⓪ ⁎ 㧊㌗㦮 㨂⬢⯒ 㩧䞿䞮㡂

┾㧒 ⁞㏣㨂⬢㢖⓪ ┺⯎ 䔏㎇㦚 Ṭ⓪ 㨂⬢㧊┺.

㩧䞿⹿⻫㦒⪲⓪ 㞫㡆㠦 㦮䞲 ⹿⻫㧊 Ṗ㧻 ἓ㩲㩗 㧊Ⳇ ⍦Ⰲ 㧊㣿♮ἶ 㧞┺[1].

䡚㨂 ㌗㣿䢪♮㠊 㧞⓪ 㧊㫛⁞㏣ 䕦㨂⓪ 㡊㩚☚

㥾, 㡊⽊㫊㥾, 㡊䣾㥾㎇㧊 ⥆㠊⋲ 㞢⬾⹎ⓚὒ ⌊ 㡒㎇, ⌊㌆㎇, ⌊㞢䃊Ⰲ㎇ ⹥ ⌊㔳㎇㧊 ⥆㠊⋲ 㓺 䎢㧎Ⰲ㓺 㓺䕎㦚 㩧䞿㔲䋾 㧊㫛⁞㏣ 䕦㨂Ṗ ╖䚲 㩗㧊┺. ⡦䞲 㧦☯㹾 ⿖䛞, 䦊╖䙆, 㩚㧦 㩲䛞 ❇ 㠦㍲ ἓ⨟䢪㠦 ╖䞲 㑮㣪Ṗ 㯳Ṗ䞾㠦 ➆⧒ 㩚㧦 䕢 㹾䘦㎇, 㧎㼊 䂲䢪㎇, ἶ゚ṫ☚ ἓ⨟ ㏢㨂㧎 Mg䞿⁞㦚 㩧䞿㔲䋾 STS-Al-Mg 㧊㫛⁞㏣ 䕦㨂 Ṳ

ٻ

XUG 䞲ῃ₆Ἒ㡆ῂ㤦G ⿖㍺G 㨂⬢㡆ῂ㏢G ⼖䡫㩲㠊㡆ῂ⁎⭏G YUG 㿿⋾╖䞯ᾦG ⋮⏎㏢㨂Ὃ䞯ὒG

JG ᾦ㔶㩖㧦aG 㧊㡗㍶SGlT”ˆ“aG“ šX]]_g’”šU™ŒU’™G

Y\_GV穢剳暒昷儆击穟箒滆V洢YW劒G 洢Z笾SGYWXX噊G G

⹲ ⹥ 㦧㣿㧊 㰚䟟♮ἶ 㧞┺. ⁎⩂⋮ Mg䞿⁞㧊 䙂䞾♲ 㧊㫛⁞㏣ ㏢㨂㠦 ╖䞲 㡆ῂ⓪ 䡚㨂₢㰖

⹎⹎䞲 ㌗䌲㧊┺.

㧊㫛⁞㏣ 䕦㨂㠦 ╖䞲 ㍶䟟㡆ῂ⪲⓪ 䔏㎇䟻㌗

㦚 㥚䞲 㡆ῂ[5~6]㢖 ㎇䡫㎇㠦 ╖䞲 㡆ῂṖ 㑮䟟

♲ ⹪ 㧞┺[7~10]. Lee[4] ❇㦖 STS-Al-Cu 㧊㫛⁞㏣

䕦㨂㦮 㠊┦Ⱇ 㻮Ⰲ㠦 ➆⯎ 㡗䟻㦚 ⿚㍳䞲 ἆὒ 㠊┦Ⱇ 㡾☚400 ଇ ἓ㤆, ἚⳊ㠦㍲ Al2Cu ㌗㧊 ⹲

㌳♮㠊 㡆㔶㥾㧊 㩖䞮♾㦚 ⽊ἶ䞮㡖┺. Manesh[5]

❇㦖Al-Fe 㧊㫛⁞㏣ 䕦㨂㦮 ἓ㤆 400ଇ㠦㍲ 16㔲 Ṛ ☯㞞 㠊┦Ⱇ 㻮Ⰲ䞮⓪ ộ㧊 ㎇䡫㎇ὒ ṫ☚㠦 Ṗ㧻 㥶Ⰲ䞾㦚 ⽊ἶ 䞮㡖┺[4]. 㧊㫛⁞㏣ 䕦㨂 㩲 㫆 Ὃ㩫 㫆Ị㠦 ╖䞲 ㍶䟟㡆ῂ✺ὒ⓪ ╂Ⰲ, ㏢㨂 㦧㣿㦚 㥚䞲 ㎇䡫㎇ 㡆ῂ⓪ ⿖㫇䞲 ㌗䌲㧊┺.

⽎ 㡆ῂ㠦㍲⓪ STS-Al-Mg 㧊㫛⁞㏣䕦㨂㦮 ㎇䡫

㎇㠦 ╖䞲 ₆㽞 ◆㧊䎆 䢫⽊⯒ 㥚䟊 1㿫 㧎㧻㔲 䠮㦚 㑮䟟䞮㡂 㡾☚㢖 ⼖䡫⮶㏣☚㠦 ➆⯎ ㏢㎇⼖

䡫 ⹥ 䕢┾䔏㎇㦚 ⿚㍳䞮㡖┺. ⡦䞲 㧊㫛⁞㏣㦚 ῂ㎇䞮ἶ 㧞⓪ ṗ ㏢㨂✺㦮 㧎㧻䔏㎇ὒ ゚ᾦ䞾㦒

⪲㖾 㧊㫛㏢㨂㦮 ㏢㎇⼖䡫 䔏㎇㠦 ⹎䂮⓪ 㧎㧦✺

㦮 㡗䟻㦚 ἶ㺆䞮ἶ㧦 䞮㡖┺.

# 51# ⎎# 㚂#

514# ⎆㚂# ∶⡖#

⽎ 㔺䠮㠦 ㌂㣿䞲 ㏢㨂⓪ ⪺ ⽎❿(roll bonding)

⻫㦒⪲ 㩲㫆♲ STS430-Al3004-AZ31 㧊㫛⁞㏣ 䕦 㨂⪲㍲ ṗ ㏢㨂㠦 ╖䞲 䢪䞯 㫆㎇㦖 Table 1ὒ ṯ┺.

Fig. 1(a)㢖 ṯ㧊 ㌗⿖⪲⿖䎆 STS430, Al3004, AZ31䞿

⁞㦚 㩗䂋䞲 䤚 㡊Ṛ㞫㡆ὒ 㡊㻮Ⰲ Ὃ㩫㦚 䐋䟊 㩲 㫆♮㠞┺. ṗ ㏢㨂㦮 ⚦℮⓪ Ὃῂ䡚⹎ἓ 䁷㩫ἆὒ STS430(0.98mm), Al3004(1.24mm), AZ31(1.63mm)㦮

⚦℮⪲ Fig. 1(b)㢖 ṯ┺.

⪺ ⽎❿⻫㦒⪲ 㧊㫛⁞㏣㏢㨂Ṗ 㩲㫆♶ ➢⓪ ㏢

㎇⼖䡫㦒⪲ 㤦㏢㨂㦮 ⶒ㎇㧊 ⼖䢪♶ 㑮 㧞㦒⸖⪲

㤦㏢㨂㦮 ⼖䡫䔏㎇㦚 㧊㫛㏢㨂 䔏㎇ ⿚㍳㠦 ⹪⪲

㩗㣿䞶 㑮 㧞⓪㰖㠦 ╖䞲 ⿚㍳㧊 䞚㣪䞮┺. ➆⧒

㍲, ⽎ 㡆ῂ㠦㍲⓪ ṗ ㏢㨂⼚㦮 ⶒ㎇㠦 ╖䞲 㔶⬆

㎇㦚 ⏨㧊₆ 㥚䞮㡂 㧊㫛⁞㏣㏢㨂⪲⿖䎆 ṗ䂋㦮

㏢㨂⯒ ⿚Ⰲ㔲䅲 㔲䘎㦚 㺚䀾䞲 䤚 㧎㧻㔲䠮㦚 㑮䟟䞮㡖┺. 㧊㫛⁞㏣ 䕦㨂㦮 㔲䠮䘎㦖 Fig. 2(a)㠦

⋮䌖⌊㠞㦒Ⳇ, ⿚Ⰲ䞮㡂 㩲㫆♲ ṗ ㏢㨂⼚ 㔲䠮䘎 㦖 Fig. 2(b)㠦 ⋮䌖⋮ 㧞┺.

ṗ 䂋㦮 ㏢㨂⯒ ⿚Ⰲ䞮₆ 㥚䟊 䢪䞯㩗 ⹿⻫㦒

⪲ 㑮㌆䢪䔎⮾(NaOH)⯒ 㧊㣿䞮㡖┺. 㑮㌆䢪⋮䔎

Table 1 Material chemical compositions

C Cr Mn Si Fe

SUS

(STS430) 0.12 16~18 1.0 1.0 Bal.

Mn Mg Fe Si Al

Al

(Al3004) 1~1.5 0.8~1.3 0.7 0.3 Bal.

Al Zn Mn Si Mg

Mg

(AZ31) 2.5~3.5 0.6~1.4 0.2~1.0 0.1 Bal.

G G G G G G G

(a) (b)

Fig. 1 Schematic diagram of roll bonding process and cross section of the multilayered sheet: (a) roll bonding process, (b) cross section

G G G G

(a) (b)

Fig. 2 Tensile specimens of multilayered sheet and separated sheet: (a) multilayered sheet, (b) separated sheet

⮾ὒ ⶒ㦮 ゚㥾㦚 6:4⪲ 䞮㡂 㔲䠮䘎㦚 ⍹ἶ ㏢㨂 Ṗ ⿚Ⰲ♶ ➢₢㰖 ᾦ⹮䞮㡖┺.

䢪䞯 ⹮㦧㔳㦖 㔳 (1)ὒ ṯ┺.

2NaOH + Al + 2H2O = 2NaAlO2 + 3H2 (1)

㔳(1)ὒ ṯ㧊 Al3004䞿⁞㦚 䢪䞯㩗㦒⪲ 㩲Ệ䞲 䤚 STS430ὒ AZ31䞿⁞㦮 䕦㨂⯒ ⿚Ⰲ䞮㡖┺. ⡦ 䞲 Al3004䞿⁞㦚 ⿚Ⰲ䞮₆ 㥚䟊 STS430ὒ AZ31 䞿⁞㦚 㩞┾䞲 䤚 㧪㫊䞮⓪ 䞿⁞㦖 㡆Ⱎ(polishing) 㻮Ⰲ䞮㡖┺. ㏢㨂 㩞┾ 㔲 ⹲㌳♮⓪ 䚲Ⳋ ⏎䂮 (notch)㠦 㦮䞲 㔲䠮䘎 㫆₆䕢┾㦚 㾲㏢䢪䞮₆ 㥚 䟊 ㏢㨂㦮 㩞┾Ⳋὒ 㡜Ⳋ㦚 㡆Ⱎ䞮㡖┺.

#

515# ⠢⡏⎆㚂#

㧊㫛⁞㏣䕦㨂㢖 ṗ 䂋Ṛ ┾㧒㏢㨂⯒ 㡾☚㢖 ⼖ 䡫⮶㏣☚㠦 ➆⯎ 㥶☯ἷ㍶㦚 䁷㩫䞮₆ 㥚䟊 ⹖䘦

P

A Y

B

ETCEMXQKF

Pressing Heating

AZ3(1.63mm) Al3004(1.24mm) STS430(0.98mm)

穢剳暒昷儆击穟箒滆V洢YW劒G 洢Z笾SGYWXX噊VY\`G

G (a) (b)

Fig. 3 Tensile test equipment and specimen : (a) tensile test equipment, (b) specimen

Table 2 Tensile test conditions Variables Values Gage length(mm) 20

Multilayer sheet : 3.85 Thickness(mm) STS430 : 0.98, Al3004 : 1.24

AZ31 : 1.63

Temperature(ଇ) Room Temp., 100, 150, 200, 250, 300, 400

Strain rate(/sec.) 10^-1 , 10^-2

䡫 Ṗ㡊⪲ ⌊㠦㍲ ἶ㡾 㧎㧻㔲䠮㦚 㔺㔲䞮㡖┺.

㩫䢫䞲 ⼖䡫⮶㦚 䁷㩫䞮₆ 㥚䟊㍲⓪ ⼖㥚䁷㩫₆ (extension meter)⯒ ⿖㹿䟊㟒 䞮㰖Ⱒ 㔏㡾♲ ㌗䌲 㧊 Ⳇ ╖⼖䡫㦚 䁷㩫䟊㟒 䞮₆ ➢ⶎ㠦 ἶ㡾 ⼖㥚䁷㩫

₆ ㌂㣿㧊 Ἲ⧖䞮㡂 㧎㧻㔲䠮₆ 㧦㼊㦮 ⼖㥚⪲

㰚⼖䡫⮶㦚 Ἒ㌆䞮㡖┺. Fig. 3(a)⓪ Ⱒ⓻㧎㧻㔲䠮₆ (UTM)㢖 䞾℮ ㌂㣿♲ Ṗ㡊⪲㧊Ⳇ, Fig. 3(b)⓪ 㧎㧻 㔲䠮䘎(ASTM-E8M-01, sub-size)㦚 ⋮䌖⌊ἶ 㧞┺.

┺䂋㏢㨂㢖 Ṳ⼚㏢㨂㦮 㧎㧻㔲䠮㫆Ị㦖 Table 2 㢖 ṯ┺.

AZ31 䞿⁞㦮 ἓ㤆 㡾☚㠦 ➆⯎ ㎇䡫㎇㦖 Ⱔ㦖

㍶䟟 㡆ῂ㧦✺㦮 㡆ῂ ἆὒ㠦 㦮䟊 ⿚㍳♲ ⹪ 㧞

┺. ㌗㡾㠦㍲ ⌄㦖 ㎇䡫㎇㦒⪲ 㧎䟊 㡾Ṛ㧊⋮ 㡊 Ṛ㠦㍲ ㎇䡫㧊 㧊⬾㠊㰖⓪ AZ31 䞿⁞㦮 㾲㩗 ㎇ 䡫㡾☚⓪ 200~300ଇ 㡗㡃㧊┺[2~4]. ⽎ 㡆ῂ㠦㍲

㌂㣿♲ 㧊㫛⁞㏣ ㏢㨂 Ṗ㤊◆ ㌗╖㩗㦒⪲ ㎇䡫㎇

㧊 Ṗ㧻 䀾㟓䞲 ㏢㨂⓪ AZ31 䞿⁞㧊┺. 3 Ṗ㰖 ㏢ 㨂 Ṗ㤊◆ Ṗ㧻 ⌄㦖 ㎇䡫㎇㦚 Ṭ⓪ ㏢㨂㦮 㡗䟻 㧊 Ṗ㧻 䋆 Ⱒ䋒, AZ31 䞿⁞㦮 㡗䟻㧎㧦⯒ ₆㭖㦒

⪲ 㡾☚ ⻪㥚⓪ 250~300ଇ⯒ ₆㭖㦒⪲ 䞮㡂 ㌗㡾⿖

䎆 400ଇ₢㰖, ⼖䡫⮶㏣☚(strain rate)⓪ 0.1, 0.01/sec.

㠦㍲ 㔲䠮䞮㡖┺. 㔲䠮䘎㦖 㡾☚ ‶㧒䢪⯒ 㥚䟊

⳿䚲㡾☚㠦㍲ 㟓 20~30min ☯㞞 㥶㰖䞮㡖┺. 㔲䠮 㡾☚ ₆㭖㦖 㡊㩚╖(thermocouple)⯒ 䐋䟊 㰗㩧 䁷 㩫♲ ㏢㨂㦮 㔺㩲 㡾☚⯒ 㧊㣿䞮㡖┺.

(a) (b) G

(c) (d) G G

(e) (f)

(g)

Fig. 4 True stress-strain curves of multilayered sheet under various strain rates at temperatures of : (a) room temp., (b) 100ଇ, (c) 150ଇ, (d) 200ଇ, (e) 250ଇ, (f) 300ଇ and (g) 400ଇ

61# ൚ඦ# Ჹ# ㉊⠂#

614# ⠞⤯າ∷㎺⡖# ⠢⡏ᵪ㚿# ㍣⇛#

㧊㫛⁞㏣ 䕦㨂㦮 㧎㧻㔲䠮 ἆὒ⪲ Fig. 4㠦 㡾☚

㢖 ⼖䡫⮶㏣☚㠦 ➆⯎ 1㿫 㧎㧻⼖䡫 Ệ☯㦚 ⋮䌖

0.00 0.05 0.10 0.15 0.20 0.25 0.30 0.35 0

50 100 150 200 250 300

350 _{0.1 /sec}

0.01 /sec

True strain

True stress [MPa]

VW

QG

=00ଇ ?

0.00 0.05 0.10 0.15 0.20 0.25 0.30 0.35 0.40 0.45 0

50 100 150 200 250

300 0.1 /sec

0.01 /sec

True stress [MPa]

True strain

VW

=ଇ ?

0.00 0.05 0.10 0.15 0.20 0.25 0.30 0.35 0

50 100 150 200 250 300

350 _{0.1 /sec}

0.01 /sec

True stress [MPa]

True strain

=ଇ ?

VW

QG

0.00 0.05 0.10 0.15 0.20 0.25 0.30 0.35 0.40 0.45 0

50 100 150 200 250

300 _{0.1 /sec}

0.01 /sec

True strain

True stress [MPa]

VW

QG

=0ଇ ?

0.00 0.05 0.10 0.15 0.20 0.25 0.30 0.35 0.40 0

50 100 150 200 250

0.1 /sec 0.01 /sec

True stress [MPa]

True strain

VW

QG

=00ଇ ?

0.00 0.05 0.10 0.15 0.20 0.25 0.30 0.35 0

50 100 150 200

250 _{0.1 /sec}

0.01 /sec

True strain

True stress [MPa]

VW

QG

=00ଇ ?

0.00 0.05 0.10 0.15 0.20 0.25 0.30

0 50 100 150 200 250 300

350 0.1 /sec

0.01 /sec

True strain

True stress [MPa]

=46 ?

VW

QG

Y]WGV穢剳暒昷儆击穟箒滆V洢YW劒G 洢Z笾SGYWXX噊G G

(a)

(b)

(c)

G G G G

(d)

(e)

(f)

(g)

Fig. 5 Fractured section of multilayered sheet under various strain rates at temperatures of : (a) room temp., (b) 100ଇ, (c) 150ଇ, (d) 200ଇ, (e) 250ଇ, (f) 300ଇ and (g) 400ଇ

⌊㠞┺. 㧒⹮㩗㧎 ┾㧒㏢㨂㢖⓪ ╂Ⰲ 2⻞㦮 ⼖ἷ 㩦㧊 ⋮䌖⋮ἶ 㧞┺. 㡾☚㠦 ➆⧒ 䕢┾ 㟧㌗㧊 㼁⻞㱎(1^st) 䕢┾ὒ ⚦⻞㱎(2^nd) 䕢┾㧊 ⹲㌳♮⓪ 㥚 䂮㢖 ㏢㨂㦮 㫛⮮Ṗ 㡾☚㢖 ⼖䡫⮶㏣☚ ➆⧒ ㌗ 㧊䞲 ἆὒ⯒ ⋮䌖⌊ἶ 㧞┺.

#

61414# ⛒ᑮ⚫㙏#

㡾☚㠦 ➆⯎ 㡗䟻㦒⪲ ㌗㡾(room temp.) ⹥ 100ଇ㠦㍲⓪ AZ3䞿⁞㧊 Ⲓ㩖 䕢┾♲ 䤚 STS430 ὒ Al3004㏢㨂Ṗ ☯㔲㠦 䕢┾♮㠞┺. ㌗㡾㧎㧻 㔲䠮㠦㍲⓪ 䋆 㡆㔶㠜㧊 䀾㎇䕢┾(brittle) 㟧㌗㦚

⽊㧊⓪◆ 㧊⓪ AZ31䞿⁞㦮 㩖㡾 䕢┾ 䔏㎇ ➢ⶎ 㧊┺. 150ଇ㠦㍲☚ STS430ὒ Al3004䞿⁞㧊 Ⲓ㩖 䕢┾♮㠞㰖Ⱒ Ệ㦮 ☯㔲㠦 䕢┾♮⓪ 㟧㌗㦚 ⋮ 䌖⌊㠞┺. ⹮Ⳋ, 200ଇ㠦㍲⓪ 3Ṗ㰖 ㏢㨂Ṗ ⳾⚦

☯㔲㠦 䕢┾♮㠞┺. 250ଇ㠦㍲⓪ STS430ὒ Al3004 䞿⁞㧊 ☯㔲㠦 AZ31䞿⁞ ⽊┺ Ⲓ㩖 䕢┾ ♮㠞┺.

ἆῃ 200ଇ ⿖⁒㦚 ἓἚ⪲ 䕢┾㟧㌗㧊 ⼖䢪♮㠊 200ଇ ⽊┺ 㩖㡾㠦㍲⓪ AZ31䞿⁞㧊 Ⲓ㩖 䕢┾♮

ἶ ⁎ ⽊┺ ἶ㡾㠦㍲⓪ ㌗╖㩗㦒⪲ STS430䞿⁞

㧊 Ⲓ㩖 䕢┾ ♮ἶ 㧞┺. 300ଇ㠦㍲⓪ STS430䞿

⁞㧊 Ⲓ㩖 䕢┾㧊 ⹲㌳♲ 䤚 Al3004, AZ31 㑲㍲

⪲ 䕢┾ ♾㦒⪲㖾 250ଇ⿖⁒㠦㍲㦮 㯳Ṗ♲ AZ31 䞿⁞ 㡆㔶 䔏㎇㧊 Ⱔ㦖 㡗䟻㦚 ⋮䌖⌊ἶ 㧞㦢㦚 㞢 㑮 㧞┺. 400ଇ㠦㍲⓪ 300ଇ㢖 㥶㌂䞲 ἓ䟻㧊 㰖Ⱒ 㽳㡆㔶㥾㦖 Ṧ㏢䞮⓪ ἆὒ⯒ ⋮䌖⌊ἶ 㧞

┺. ṗ 㡾☚ ⼚ 䕢┾ 㟧㌗ ⿚㍳㦖 Fig. 5 䕢┾Ⳋ

㌂㰚㠦㍲ 䢫㧎䞶 㑮 㧞┺. Fig. 5(a)~(g)㠦 䕢┾Ⳋ

㌂㰚㠦㍲ 200ଇ⯒ ₆㭖㦒⪲ 㼁⻞㱎 䕢┾ὒ ⚦⻞

㱎 䕢┾㧊 ⹲㌳♮⓪ ㏢㨂 㫛⮮㢖 ἓ䟻㧊 ⼖䢪♮

㠞┺.

㡾☚㯳Ṗ㠦 ➆⧒ 䟃⽋ṫ☚ ⹥ 㧎㧻ṫ☚⓪ Ṧ

㏢䞮Ⳇ 250~300ଇ㠦㍲ ‶㧒㡆㔶㥾ὒ 㽳㡆㔶㥾㧊

┺㏢ 㯳Ṗ䞮⓪ ἓ䟻㦚 ⋮䌖⌊ἶ 300ଇ 㧊䤚⿖䎆

⓪ Ṧ㏢䞮ἶ 㧞㦢㦚 Fig. 6(a), (b), (c)㠦㍲ 䢫㧎䞶 㑮 㧞┺.

61415# ᵪ㚿ᨊ# ∷ᑮ# ⚫㙏#

Fig. 6(d)⓪ 㡾☚㢖 ⼖䡫⮶ ㏣☚㠦 ➆⯎ ‶㧒㡆 㔶㥾㦚 ⋮䌖⌊ἶ 㧞┺. 㡾☚ 㯳Ṗ㠦 ➆⧒ 200~

250ଇῂṚ ₢㰖⓪ ‶㧒㡆㔶㥾㧊 㯳Ṗ♮㠞┺.

0.01/sec.㧒➢Ṗ 0.1/sec.⽊┺ ㌗╖㩗㦒⪲ 䋆 ‶㧒 㡆㔶㥾㦚 ⋮䌖⌊㠞┺. ⁎⩂⋮ 200~350ଇ㠦㍲⓪ ⼖ 䡫⮶ ㏣☚Ṗ ㌗╖㩗㦒⪲ ⏨㦖 0.1/sec.㠦㍲ ⽊┺

䋆 ‶㧒㡆㔶㥾㦚 ⋮䌖⌊ἶ 㧞┺. 㧊⩂䞲 䡚㌗㦖 STS430

Al3004 AZ31

STS430 Al3004 AZ31

STS430 Al3004 AZ31

STS430 Al3004 AZ31

STS430 Al3004 AZ31

STS430 Al3004 AZ31

STS430 Al3004 AZ31

穢剳暒昷儆击穟箒滆V洢YW劒G 洢Z笾SGYWXX噊VY]XG

G

0.00 0.03 0.06 0.09 0.12 0.15 0.18 0

20 40 60 80 100 120 140

160_{Room Temp.} Al3004_0.01 /sec

Al3004_0.1 /sec

True stress (MPa)

True strain 0.00 0.05 0.10 0.15 0.20 0.25 0.30

0 100 200 300 400 500 600

700_{Room Temp.} STS430_0.01 /sec

STS430_0.1 /sec

True stress (MPa)

True strain

0.00 0.04 0.08 0.12 0.16 0.20

0 50 100 150 200 250 300 350

400_{Room Temp.} AZ31_0.01 /sec

AZ31_0.1 /sec

True stress (MPa)

True strain

(a) (b)

(c) (d)

Fig. 6 Yield, tensile strength and elongation at each temperature and strain rate : (a) yield strength, (b) tensile strength, (c) total elongation, (d) uniform elongation

(a) (b)

Fig. 7 Uniform elongation and limit dome height of AZ31 at each temperature and strain rate : (a) uniform elongation, (b) limit dome height

AZ31䞿⁞㦮 䔏㎇㦚 ➆⯊⓪ ộ㦒⪲ Fig. 7(a), (b)㠦

㍲ 㞢 㑮 㧞❅㧊 AZ31䞿⁞㦖 ⼖䡫⮶ ㏣☚Ṗ 㯳Ṗ

♶㑮⪳ ‶㧒㡆㔶㥾㧊 㯳Ṗ♮⓪ 䡚㌗㦒⪲⿖䎆 ⁎ 㤦㧎㦚 ㍺ⳛ䞶 㑮 㧞┺.

615# ᎒⻟# ೆᵮ∶⡖# ⠢⡏⎆㚂# #

⪺ ⽎❿ 䤚 㧊㫛⁞㏣㦚 ῂ㎇䞮ἶ 㧞⓪ ṗ ㏢㨂

✺㧊 ㏢㎇⼖䡫䔏㎇㠦 ⹎䂮⓪ 㡗䟻㧊 ⶊ㠝㧎㰖 㤦 㧎 ⿚㍳㦚 㥚䟊 ┺䂋㏢㨂⯒ ṗṗ㦮 ┾䂋 Ṳ⼚㏢

㨂⪲ ⿚Ⰲ䞮㡖┺. ⿚Ⰲ♲ ṗ Ṳ⼚㏢㨂⯒ ㌂㣿䞮㡂

┺䂋㏢㨂 㧎㧻㔲䠮ὒ ☯㧒 㫆Ị㦒⪲ 㔲䠮㦚 㑮䟟 䞮㡂 ἆὒ⯒ ゚ᾦx⿚㍳ 䞮㡖┺.

(a) (b)

(c)

Fig. 8 True stress-strain curve of results at each material at room temperature : (a) STS430, (b) Al3004, (c) AZ31

(a) (b)

(c) (d)

(e) (f)

Fig. 9 True stress-strain curve of each material at high temperature : (a) STS430 250ଇ, (b) STS430 300ଇ, (c)Al3004 250ଇ, (d) Al3004 300ଇ, (e) AZ31 250ଇ, (f) AZ31 300ଇ

0.00 0.03 0.06 0.09 0.12 0.15 0.18 0

100 200 300 400 500 600

True stress (MPa)

True strain

0.01 /sec 0.1 /sec Temp. 250

0.00 0.05 0.10 0.15 0.20 0.25 0

20 40 60

80 0.01 /sec

0.1 /sec

True stress (MPa)

True strain Temp. 250

0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0

20 40 60 80 100

120 _{0.01 /sec}

0.1 /sec

True stress (MPa)

True strain Temp.250

0.00 0.03 0.06 0.09 0.12 0.15 0.18 0

100 200 300 400 500

True stress (MPa)

True strain

0.01 /sec 0.1 /sec Temp. 300

0.00 0.05 0.10 0.15 0.20 0.25 0

10 20 30 40 50 60

70 _{0.01 /sec}

0.1 /sec

True stress (MPa)

True strain Temp. 300

0.0 0.1 0.2 0.3 0.4 0.5 0.6

0 20 40 60 80 100 120 140

160 _{0.01 /sec}

0.1 /sec

True strain

True stress (MPa)

Temp. 300 100 150 200 250 300 350 400

100 125 150 175 200 225

250 0.1/sec.

0.01/sec.

Yield stress (MPa)

Temperature (qC)

100 150 200 250 300 350 400 100

150 200 250 300

350 0.1/sec.

0.01/sec.

Temperature (qC)

Tensile stress (MPa)

1E-3 0.01 0.1

0.1 0.2 0.3 0.4 0.5

Uniform Elongation

Strain Rate(/sec.) 200^oC 250^oC 300^oC 350^oC 400^oC

0.01 0.1 1

35 40 45

50 Temperature(^oC)

200 250 300 350 400

Limit Dome Height(mm)

Strain Rate (S^-1 )

0.5 100 150 200 250 300 350 400 450

0 20 40 60

Total elongation

Temperature (^oC)

0.1 /sec 0.01 /sec

0 50 100 150 200 250 300 350 400 450 0.10

0.15 0.20 0.25 0.30

Uniform elongation

Temperature (qC) 0.01 /sec. 0.1 /sec.

Y]YGV穢剳暒昷儆击穟箒滆V洢YW劒G 洢Z笾SGYWXX噊G G

AZ31 Multila yer

STS430

Al3004

RT 250 300

0 100 200 300 400 500 600

Yield stress (MPa)

Temperature (qC)

Multilayer 0.1/sec AZ31 0.1/sec Al3004 0.1/sec STS430 0.1/sec Multilayer 0.01/sec AZ31 0.01/sec Al3004 0.01/sec STS430 0.01/sec

AZ31

multila yer STS430

Al3004

RT 250 300

0 100 200 300 400 500 600 700

800 Multilayer 0.1/sec AZ31 0.1/sec Al3004 0.1/sec STS430 0.1/sec Multilayer 0.01/sec AZ31 0.01/sec Al3004 0.01/sec STS430 0.01/sec

Tensile stress (MPa)

Temperature (qC)

RT 250 300

0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7

0.8 Multilayer 0.1/sec AZ31 0.1/sec Al3004 0.1/sec STS430 0.1/sec Multilayer 0.01/sec AZ31 0.01/sec Al3004 0.01/sec STS430 0.01/sec

Total elongation

Temperature (qC) AZ31

Multila yer

STS430 Al3004

61514# ⛒ᑮ# Ჹ# ᵪ㚿ᨊ∷ᑮ⠂# ⚫㙏#

Fig. 8㦖 ┾䂋 Ṳ⼚㏢㨂 ㌗㡾 㧎㧻㔲䠮 ἆὒ⯒

⋮䌖⌊㠞┺. Fig. 8(a)㠦㍲㦮 STS430㦖 450MPa 㑮 㭖㠦㍲ 䟃⽋㧊 㔲㧧♮㠊 550MPa 㧊㌗㦮 㧎㧻ṫ☚, 0.25㦮 㡆㔶㥾㦚 ⋮䌖⌊ἶ 㧞┺. ⹮Ⳋ Al3004㢖 AZ31㦖 0.15㑮㭖㦮 ⌄㦖 㡆㔶㥾㦚 Fig. 8(b), (c)⯒

䐋䟊 ⋮䌖⌊ἶ 㧞┺. ㌗㡾 ㌗䌲㠦㍲⓪ ⼖䡫⮶ ㏣

☚㦮 㡗䟻㦖 ⋮䌖⋮㰖 㞠ἶ 㧞┺. ㌗㡾㠦㍲⓪ 3Ṗ 㰖 ㏢㨂 ⳾⚦ ⼖䡫⮶㏣☚㦮 㡗䟻㧊 Ệ㦮 㠜㦒Ⳇ, 㧊ộ㦖 㧒⹮㩗㧎 䡚㌗㧊┺. 㔲䠮㦮 㔶⬆㎇㦚 ⏨㧊

₆ 㥚䟊 ┺䂋㏢㨂㢖 ☯㧒 㫆Ị㧎 250¥300ଇ㠦㍲

㧎㧻㔲䠮㦚 㑮䟟䞮㡖┺. Ṳ⼚ ㏢㨂 ἶ㡾㔲䠮 ἆὒ STS430㦖 㡾☚Ṗ 㯳Ṗ䞾㠦 ➆⧒ 㡆㔶㥾㧊 Ṧ㏢䞾 㦚 Fig. 9(a), (b)⯒ 䐋䟊 㞢 㑮 㧞┺. 䞲䘎 㡾☚Ṗ 㯳Ṗ䞶㑮⪳ 㡆㔶㥾㦖 Ṧ㏢䞮⓪ ἓ䟻㦚 ⽊㧊⓪◆

㧊⩂䞲 䡚㌗㦖 ☯㩗⼖䡫⮶㔲䣾(dynamic strain aging) 䡚㌗ὒ ὖ⩾♮㠊 ⋮䌖⋲┺ἶ ⽊ἶ♮㠊 㧞┺[9]. ⡦ 䞲 Fig. 9(c)~(f)㠦㍲ Al3004㦮 ἓ㤆 ⼖䡫⮶ ㏣☚

0.1/sec.㠦㍲⓪ 䟃⽋ὒ ☯㔲㠦 䕢┾㧊 ⹲㌳䞮㡖ἶ 0.01/sec.㠦㍲ ‶㧒 㡆㔶 ⹥ 㽳㡆㔶㥾㧊 ⏨Ợ ⋮䌖

⌂┺. AZ31㏢㨂⓪ ἶ㡾㠦㍲ 㡆㔶㥾㧊 㟓3⺆ 㧊㌗

㯳Ṗ 䞮㡖㦒Ⳇ ⼖䡫⮶㏣☚Ṗ 㯳Ṗ 䞶㑮⪳ 㧎㧻ṫ

☚Ṗ 㯳Ṗ䞾㦚 㞢 㑮 㧞┺.

616# ᎒⻟# ೆᵮ∶⡖⛪# ⠞⤯າ∷∶⡖# ᵪ㚿㍣

⇛# ඪ൮#

⪺ ⽎❿㦒⪲ 㩧䞿♲ 㧊㫛⁞㏣ ㏢㨂㧎 ┺䂋㏢㨂 㢖 ṗṗ ⿚Ⰲ♲ ┾䂋 Ṳ⼚㏢㨂㢖㦮 䔏㎇㦚 ゚ᾦxG

⿚㍳䞮㡖┺. 1㿫 㧎㧻㦮 ₆⽎㩗㧎 ⼖䡫䔏㎇㧎 䟃

⽋ṫ☚, 㾲╖㧎㧻ṫ☚ ⁎Ⰲἶ 㡆㔶㥾㠦 ╖䞲 ἆὒ

⯒ Fig. 10㠦 ⋮䌖⌊㠞┺. Fig. 10(a), (b)㠦 ⋮䌖⋮㧞

⓪ 䟃⽋ṫ☚ ⹥ 㾲╖㧎㧻ṫ☚⓪ STS430䞿⁞㧊 ┺

⯎ 䞿⁞㠦 ゚䟊 䡚㩖䧞 ⏨Ợ ⋮䌖⌂┺. ⁎Ⰲἶ AZ31䞿⁞㦮 ἓ㤆 㡾☚Ṗ 㯳Ṗ䞾㠦 ➆⧒ 䟃⽋ṫ☚

Ṗ Ṧ㏢䞮Ⳇ 250~300ଇ㠦㍲ 䋆 㹾㧊Ṗ 㠜㦢㦚 㞢 㑮 㧞┺. Al3004䞿⁞㦮 ἓ㤆 ⼖䡫⮶㏣☚㢖 㡾☚ 㯳 Ṗ㠦 ὖἚ 㠜㧊 䟃⽋ṫ☚㢖 㾲╖㧎㧻ṫ☚⓪ 㥶㌂

䞮Ợ ⋮䌖⌂┺. ┺䂋㏢㨂 㩲㫆⯒ 㥚䞲 㭧Ṛ㏢㨂⪲

㩧䞿㠦 䋂Ợ ὖ㡂䞮㰖Ⱒ 㩚㼊㩗㧎 ⶒ㎇㠦⓪ 䋆 㡗䟻㦚 ⹎䂮㰖 㞠㦢㦚 㞢 㑮 㧞┺.

㡆㔶㥾㠦 ╖䞲 ゚ᾦ ἆὒ⯒ Fig. 10(c)㠦 ⋮䌖⌊

㠞┺. STS430䞿⁞㦮 ἓ㤆 㡾☚Ṗ 㯳Ṗ䞾㠦 ➆⧒

㡆㔶㥾㦖 Ṧ㏢䞮㡖┺. ⡦䞲 ┺⯎ ㏢㨂㢖⓪ ╂Ⰲ

⼖䡫⮶ ㏣☚Ṗ ⓦⰊ㑮⪳ 㡆㔶㥾㧊 ⌄Ợ ⋮䌖⋮ἶ 㧞┺. Al3004䞿⁞㦮 ἓ㤆 㡆㔶㥾㦮 ⼖䢪⓪ 䋂Ợ ⋮

(a)

(b)

(c)

Fig.10 Comparison graph of yield, tensile strength and elongation at temperature at each material and multilayered sheet : (a) yield stress, (b) tensile stress, (c) total elongation

䌖⋮㰖 㞠㞮㰖Ⱒ, AZ31䞿⁞㦖 250~300ଇ㠦㍲ 䡚㩖 䧞 㯳Ṗ䞾㦚 㞢 㑮 㧞ἶ 㡾☚㯳Ṗ㢖 ⼖䡫⮶㏣☚

㠦 ➆⧒ 㡆㔶㥾㧊 ⼖䢪♮⓪ 䡚㌗㦖 AZ31䞿⁞㦮 㡗䟻㦒⪲ 䕦┾♮Ⳇ, ┺䂋㏢㨂㦮 㽳㡆㔶㥾㠦 㭒♲

㡗䟻㦚 ⹎䂾㦚 㞢 㑮 㧞┺.

㧊㫛⁞㏣ ㏢㨂⯒ ṗṗ 㩞┾䞲 ┾䂋㏢㨂⯒ 㧊㣿 䞮㡂 250~300ଇ㠦㍲ ⼖䡫⮶ ㏣☚㠦 ➆⧒ ṗ ㏢㨂 㦮 㥶☯ἷ㍶(㦧⩻-⼖䡫⮶) 䞿㠦 ╖䞲 䘟‶ Ṩ㦚G G

穢剳暒昷儆击穟箒滆V洢YW劒G 洢Z笾SGYWXX噊VY]ZG

G (a) (b)

(c) (d)

(e) (f)

Fig.11 The flow stress curves and considering the thickness by each material : (a) room temperature strain rate 0.1/sec, (b) room temperature strain rate 0.01/sec, (c) 250ଇ strain rate 0.1/sec, (d) 250ଇ strain rate 0.01/sec, (e) 300ଇ strain rate 0.1/sec, (f) 300ଇ strain rate 0.01/sec

゚ᾦ 䞮㡖┺. ⡦䞲 ṗ ㏢㨂⼚ ⶒ㎇ ◆㧊䎆㠦 ⪺

⽎❿㦒⪲ 㩧䞿♲ ┺䂋㏢㨂㦮 ㏢㨂 ⚦℮⯒ ἶ⩺䞲 䘟‶Ṩ㦒⪲ ゚ᾦ·⿚㍳ 䞮㡖┺.

゚ᾦ 㔳㦖 㔳(2), (3)ὒ ṯ┺.

㥶☯ἷ㍶ 䞿㠦 ╖䞲 ╖㑮㩗 䘟‶Ṩ

[(STS430) + (Al3004) + (AZ31)]/3 (2)

⚦℮⯒ ἶ⩺䞲 䘟‶Ṩ

[ta(STS430) + tb(Al3004) + tc (AZ31)]/Tt (3)

㔳 (3)㠦㍲ ta⓪ STS430㏢㨂㦮 ⚦℮, tb, tc⓪ Al3004㢖 AZ31㏢㨂㦮 ⚦℮⯒ tt⓪ 㧊㫛⁞㏣㏢㨂

㩚㼊 ⚦℮⯒ ⋮䌖⌊ἶ 㧞┺.

㡾☚ ⹥ ⼖䡫⮶㏣☚Ṗ 㯳Ṗ䞾㠦 ➆⧒ (2), (3)㔳 㠦 㦮䟊 Ἒ㌆♲ 㥶☯㦧⩻㦚 Fig. 11㠦 ⋮䌖⌊㠞┺.

⚦ 㑮㔳 ⳾⚦ ㌗㡾㠦㍲ ⋮䌖⋮⓪ 2⻞㦮 䕢┾ 䡚

㌗(⼖ἷ)㦚 㡞䁷䞶 㑮⓪ 㠜㠞㦒Ⳇ, 㦧⩻㦖 ⚦℮⯒

ἶ⩺䞲 ἓ㤆Ṗ ⽊┺ 㥶㌂䞲 ἓ䟻㦚 ⋮䌖⌊ἶ 㧞

⓪ ⹮Ⳋ, 㡆㔶㥾㦖 ☯㧒䞲 ἓ䟻㦚 ⋮䌖⌊㰖 㞠ἶ 㧞┺. 㧊⩂䞲 㡆㔶㥾㦮 㡞䁷 㠊⩺㤖㦖 Ṳ⼚㏢㨂㦮 㡆㔶㥾 㧊㣎㠦 Ṳ⼚㏢㨂Ṛ ἚⳊ 㩧䞿⩻㧊 㧧㣿䞮 ἶ 㧞₆ ➢ⶎ㦒⪲ 䕦┾♲┺.

71# ൚# ᤊ#

⽎ 㡆ῂ㠦㍲⓪ STS430-Al3004-AZ31 ┺䂋㏢㨂㢖

┾䂋㏢㨂㦮 ㏢㎇⼖䡫 䟊㍳㠦 䞚㣪䞲 㥶☯㦧⩻ 䔏

㎇㦚 ゚ᾦ䞾㦒⪲㖾 ┺㦢ὒ ṯ㦖 ἆ⪶㦚 㠑㠞┺.G G (1) 㧊㫛⁞㏣ 䕦㨂㦮 ἶ㡾 㧎㧻㔲䠮㦚 䐋䟊 100~

150ଇ㠦㍲⓪ AZ31䞿⁞㧊 STS430, Al3004䞿⁞ ⽊

┺ Ⲓ㩖 䕢┾♮ἶ 200ଇ㠦㍲⓪ 3Ṗ㰖 ㏢㨂Ṗ ☯ 㔲㠦 䕢┾♮㠞┺. 250ଇ㧊㌗㦮 㡾☚㠦㍲⓪ AZ31䞿

⁞㦮 ㎇䡫㎇㧊 䟻㌗♮㠊 STS430, Al3004䞿⁞㧊 AZ31䞿⁞ ⽊┺ Ⲓ㩖 䕢┾♮㠞┺.

(2) 㧊㫛⁞㏣ ㏢㨂㦮 㧎㧻ṫ☚⓪ ṗ ㏢㨂(STS430, Al3004, AZ31)㦮 Ṳ⼚㩗 㧎㧻ṫ☚㦮 㥶䣾(rule of mixture) Ṩ㦒⪲ ⋮䌖⋮ἶ 㧞㦒Ⳇ 㧊㫛⁞㏣㦮 㾲╖

㧎㧻ṫ☚⓪ ㌗╖㩗㦒⪲ Ṗ㧻 ṫ☚Ṗ ⏨㦖 ㏢㨂㧎 STS430䞿⁞㦮 㡗䟻㦚 ⹱ἶ 㧞┺.

(3) ㌗㡾㠦㍲⿖䎆 㡾☚㯳Ṗ㠦 ➆⧒ ‶㧒㡆㔶㥾 㧊 㯳Ṗ♮㠊 200~250ଇῂṚ㠦㍲⓪ ㌗㡾⽊┺ 2⺆

㧊㌗ 㯳Ṗ♮㠊 0.2㧊㌗㦚 ⋮䌖⌊㠞┺.

(4) ⼖䡫⮶ ㏣☚㠦 ➆⧒ ⼖䢪Ṗ Ệ㦮 㠜⓪ 䟃⽋

ṫ☚㢖⓪ ╂Ⰲ ‶㧒㡆㔶㥾㦖 䞾℮ 㯳Ṗ♮㠞┺.

200~350ଇῂṚ㠦㍲⓪ ⼖䡫⮶ ㏣☚Ṗ ㌗╖㩗㦒⪲

⏨㦖 0.1/sec. ἓ㤆Ṗ 0.01/sec.⽊┺ 䋆 ‶㧒㡆㔶㥾 㦚 ⋮䌖⌊㠞┺.

(5) 㧊㫛⁞㏣㏢㨂㦮 㡾☚㢖 ⼖䡫㥾㏣☚㠦 ➆⯎

㡆㔶㥾 ⼖䢪⓪ AZ31䞿⁞㦮 䔏㎇ὒ ☯㧒䞲 㟧㌗㦚

⋮䌖⌊㠞┺. ἆῃ, 㧊㫛⁞㏣㏢㨂㦮 ṫ☚⓪ ῂ㎇㏢

㨂✺ Ṗ㤊◆ ṫ☚Ṗ 㤆㑮䞲 ㏢㨂(STS430)Ṗ, ㎇䡫

㎇㦖 Ṗ㧻 䀾㟓䞲 ㏢㨂(AZ31)Ṗ 㰖⺆㩗㧎 㡗䟻㦚 㭒ἶ 㧞┺.

㝮 ໚ G

⽎ 㡆ῂ⓪ ㏢㨂㤦㻲㌂㠛(㌗⼖䌲/㧚Ἒ㩲㠊 㩧䞿

0.00 0.03 0.06 0.09 0.12 0.15 0.18 0

50 100 150 200 250 300 350 400

True stress (MPa)

True strain Exp. (clad) Thick. (clad) AVG. (clad)

Temp. : Room temp. , Strain rate : 0.1 /sec

0.000.05 0.10 0.150.20 0.25 0.30 0.35 0

50 100 150 200 250 300 350 400

Temp. : Room temp. , Strain rate : 0.01 /sec Exp. (clad) Thick. (clad) Avg. (clad)

True stress (MPa)

True strain

0.00 0.05 0.10 0.15 0.20 0.25 0.30 0.35 0.40 0

50 100 150 200 250

Temp. : 250 qC, Strain rate : 0.1/sec Exp. (clad) Thick. (clad) Avg. (clad)

True Stress(MPa)

True strain 0.00 0.05 0.10 0.15 0.20 0.25 0.30 0.35 0.40 0

50 100 150 200 250

Temp. : 250 qC, Strain rate : 0.01/sec Exp. (clad) Thick. (clad) Avg. (clad)

True strain

True Stress(MPa)

0.00 0.05 0.10 0.15 0.20 0.25 0.30 0.35 0

50 100 150 200 250

True stress(MPa)

True strain Exp. (clad) Thick. (clad) Avg. (clad)

Temp. : 300 qC, Strain rate : 0.1/sec

0.00 0.05 0.10 0.15 0.20 0.25 0.30 0.35 0

50 100 150 200 250

True stress(MPa)

True strain Exp. (clad) Thick. (clad) Avg. (clad)

Temp. : 300 qC, Strain rate : 0.01/sec

Y][GV穢剳暒昷儆击穟箒滆V洢YW劒G 洢Z笾SGYWXX噊G G

⁞㏣㏢㨂 ㍺Ἒ₆㑶, ὒ㩲⻞䢎 M-2009-01-0014)㦮 㧒䢮㦒⪲ 㑮䟟♮㠞㦒Ⳇ 㧊㠦 ὖἚ㧦 㡂⩂⿚℮ Ṧ

㌂ ✲Ⱃ┞┺.

Ⳣ ඊ ᯢ 㙶

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Koseki, 2010, Experimental and numerical analysis of multilayered steel sheets upon bending, J. of Mater. Process. Tech., Vol.210, pp. 1926~1933.# [9] J. M. Robinson, M. P. Shaw, 1994, Microstructural

and mechanical influences on dynamic strain aging phenomena, Int, Mater. Rev., Vol. 39, pp. 113~112.# [10] J. H. Jung, Y. S. Lee, Y. N. Kwon, J.H. Lee, 2008,

Forming limits diagram of AZ31 alloy sheet with the deformation mode, Trans. Mater. Process. Tech., Vol.17, No.7, pp. 473~480.#